1. Field of the Invention
The invention relates to an apparatus, method and a computer program for testing an electric wiring system and a computer-readable storage medium having stored thereon a computer program for testing an electric wiring system.
2. Description of the Related Art
An electric wiring system, such as a wiring harness, has a plurality of contacts that form a predetermined electric network. The contacts that are required to form a proper network are determined at the time of designing.
Electrical tests for such an electric wiring system include a dielectric strength test for testing dielectric strengths of the contacts insulated from each other and an electrical connection test for discriminating whether connected/disconnected states of the contacts form a proper network.
In these electrical tests, specific contacts to be tested normally are selected from a plurality of contacts, connected/disconnected states of all the possible combinations of the selected contacts are detected, and whether the detected connected/disconnected states are satisfactory are discriminated.
However, if an electrical test is conducted for all the possible combinations of the respective contacts, a number of tests xe2x80x9cNxe2x80x9d is: N=m(mxe2x88x921) where m denotes a total number of contacts in the case of a bilateral test. Thus, if the total number xe2x80x9cmxe2x80x9d of the contacts is doubled, the number of tests xe2x80x9cNxe2x80x9d is increased to about a square of the previous number. The number of tests increases excessively for a product having a large number of circuits (e.g. 200 circuits) due to the advanced electronization of recent electric wiring systems, and it disadvantageously takes a considerable time for the electrical tests.
In view of the above problem, an object of the present invention is to allow to quickly electrically test the electric wiring system having a large number of contacts by maximally reducing the number of electrical tests.
The invention is directed to an electrical wiring system testing apparatus for testing connected states of contacts of an electrical wiring system with a plurality of contacts that form an electric network. The system comprises a reference data storage means for storing reference data used as references in testing the connected states. The system also comprises reading means for reading the connected states of the electrical wiring system and a discriminating means for discriminating the connected states of the electrical wiring system by comparing the test data read by the reading means with the reference data stored in the reference data storage means. Contacts in the reference data are divided into a plurality of groups insulated from each other. The discriminating means first discriminates insulated states of the respective contacts among the respective groups and then discriminates in the respective groups if the insulated states of the respective groups are satisfactory.
Accordingly, the insulated states of the respective contacts are first discriminated among the respective groups (inter-group discrimination) and then discriminated in the respective groups (intra-group discrimination) if the insulated states of the respective groups are judged to be satisfactory. Thus, the total number of the tests can be reduced considerably by conducting the inter-group test as compared to a case where tests are conducted for all possible combinations of all the contacts.
The discriminating means preferably tests the respective contacts in parallel in the respective groups. Thus testing time can be shortened because the contacts divided into a plurality of groups can be tested simultaneously.
The number of the contacts in each group is set preferably using a square root of a total number of the contacts as a target value. In this way, all contacts can be tested electrically by a minimum number of tests.
The reading means preferably comprises multiplexing means to enable a multiplexing communication with the plurality of contacts. Accordingly, the testing apparatus can be more flexible for different testing applications and/or the number of buses or connections can be reduced.
A controller preferably sets the contacts to specified electrical states (e.g. pulled-up to a specified voltage level by a pull-up transistor) for allowing the test data to be read by the reading means from the contacts.
The invention also is directed to a method for testing connected states of contacts of an electrical wiring system. The method includes dividing the contacts into a plurality of groups insulated from each other based on reference data. The method proceeds with a first discriminating step (inter-group discrimination) in which insulated states of the respective contacts are discriminated among the respective groups. The method continues with a second discriminating step (intra-group discriminating step) in which it is discriminated in the respective groups if the insulated states of the respective groups are satisfactory.
The invention also is directed to a computer program containing program code means for performing all the steps of the above-described method when the program is run on a computer.
The invention also is directed to a computer-readable storage means for storing a computer program containing program code means for performing all the steps of the method when said program is run on a computer.
The invention further is directed to an electrical wiring system testing program for testing connected states of contacts of an electrical wiring system having a plurality of contacts forming an electric network or a storage medium for storing such a program. The program causes the electrical wiring system testing apparatus that comprises the reference data storage means to store the reference data used as the references in testing the connected states. A reading means reads the connected states of the electrical wiring system and a discriminating means discriminates the connected states of the electrical wiring system by comparing the test data read by the reading means with the reference data stored in the reference data storage means. More particularly, the discriminating means first discriminates the insulated states of the respective contacts among the respective groups and then discriminates them in the respective groups if the insulated states of the respective groups are judged to be satisfactory based on the reference data in which the contacts are divided into a plurality of groups insulated from each other.
The invention also is directed to a computer program product comprising program code means stored on a computer-readable medium for performing the above-described method.
In the present invention, the xe2x80x9celectrical testxe2x80x9d preferably refers to an electrical connection test, but it is not restricted thereto. For example, the electrical test may be a dielectric strength test for testing a dielectric strength against a high voltage/current although a proximity condition during grouping should be additionally met.
These and other objects, features and advantages of the present invention will become more apparent upon reading of the following detailed description of preferred embodiments and accompanying drawings. It should be understood that even though embodiments are described separately, single features thereof may be combined to additional embodiments.